title: Thyroid function after unilateral total lobectomy: risk factors for postoperative hypothyroidism.
abstract: OBJECTIVE
  To evaluate the incidence of postoperative hypothyroidism among patients who underwent unilateral total lobectomy and identify related factors.
  
  
  METHODS
  Retrospective medical record analysis.
  
  
  METHODS
  Oncological center and private clinic.
  
  
  METHODS
  From March 1996 to July 2005, 228 euthyroid patients underwent unilateral total lobectomy for benign diseases; 168 had all the information required for inclusion in this study.
  
  
  METHODS
  Serum levels of thyrotropin and antithyroidal antibodies were assessed, as well as ultrasonographic evaluation of the remaining thyroid lobe and review of all histological specimens, with emphasis on lymphocytic infiltration. Hypothyroidism was defined as thyrotropin level greater than 5.5 mU/L.
  
  
  RESULTS
  Most patients were female (88%), with a median (range) age of 45 (16-72) years. Hypothyroidism occurred in 61 cases (32.8%), during a median follow-up period of 29 months (range, 6-108 months). Statistically related factors included higher preoperative thyrotropin levels (2.1 mU/L among hypothyroid patients vs 1.2 mU/L in euthyroid patients; P < .001), smaller thyroid remnant volume (3.9 mL vs 6.0 mL, respectively; P = .003); right vs left lobectomy (P = .006), and higher thyroperoxidase antibody serum levels (P = .009).
  
  
  CONCLUSIONS
  Postoperative hypothyroidism appeared in 32.8% of the cases in this series, especially among patients with elevated preoperative thyrotropin and postoperative thyroperoxidase antibody levels, after right lobectomy and when a smaller thyroid remnant was left. After confirmation with larger prospective series, these results may support the indication for early postoperative hormone supplementation in these instances.
authors.affiliation: Department of Head and Neck Surgery, University of São Paulo Medical School, São Paulo, Brazil. decarlucci@uol.com.br
authors.forename: Dorival
authors.initials: D
authors.lastname: De Carlucci
authors.forename: Marcos Roberto
authors.initials: MR
authors.lastname: Tavares
authors.forename: Marcos Takeo
authors.initials: MT
authors.lastname: Obara
authors.forename: Leandro Augusto Liporoni
authors.initials: LA
authors.lastname: Martins
authors.forename: Flávio Carneiro
authors.initials: FC
authors.lastname: Hojaij
authors.forename: Claudio Roberto
authors.initials: CR
authors.lastname: Cernea
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001938:Brazil; D015331:Cohort Studies; D005260:Female; D006042:Goiter / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology*; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D013960:Thyroid Function Tests; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods*; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism; D013974:Thyroxine / Q000032:analysis / Q000378:metabolism / Q000627:therapeutic use
chemical_list: D013972:Thyrotropin; D013974:Thyroxine